Verbose validation error is difficult to understand

[svaccari]

Hi, I was validating this Polygon that has a linear rings with different start/end coordinates:

{
    "type": "Feature",
    "geometry": {
        "type": "Polygon",
        "coordinates": [
            [
                [-55.9947406591177, -9.26104045526505],
                [-55.9976752102375, -9.266589696568962],
                [-56.00200328975916, -9.264041751931352],
                [-55.99899921566248, -9.257935213034594],
                [-55.99477406591177, -9.26103945526505],
            ]
        ],
    },
}

And I received the following message:

18 validation errors for Feature
geometry -> type
  unexpected value; permitted: 'Point' (type=value_error.const; given=Polygon; permitted=['Point'])
geometry -> coordinates
  wrong tuple length 1, expected 2 (type=value_error.tuple.length; actual_length=1; expected_length=2)
geometry -> coordinates
  wrong tuple length 1, expected 3 (type=value_error.tuple.length; actual_length=1; expected_length=3)
geometry -> type
  unexpected value; permitted: 'MultiPoint' (type=value_error.const; given=Polygon; permitted=['MultiPoint'])
geometry -> coordinates -> 0
  wrong tuple length 5, expected 2 (type=value_error.tuple.length; actual_length=5; expected_length=2)
geometry -> coordinates -> 0
  wrong tuple length 5, expected 3 (type=value_error.tuple.length; actual_length=5; expected_length=3)
geometry -> type
  unexpected value; permitted: 'LineString' (type=value_error.const; given=Polygon; permitted=['LineString'])
geometry -> coordinates
  ensure this value has at least 2 items (type=value_error.list.min_items; limit_value=2)
geometry -> type
  unexpected value; permitted: 'MultiLineString' (type=value_error.const; given=Polygon; permitted=['MultiLineString'])
geometry -> coordinates
  All linear rings have the same start and end coordinates (type=value_error)
geometry -> type
  unexpected value; permitted: 'MultiPolygon' (type=value_error.const; given=Polygon; permitted=['MultiPolygon'])
geometry -> coordinates -> 0 -> 0
  ensure this value has at least 4 items (type=value_error.list.min_items; limit_value=4)
geometry -> coordinates -> 0 -> 1
  ensure this value has at least 4 items (type=value_error.list.min_items; limit_value=4)
geometry -> coordinates -> 0 -> 2
  ensure this value has at least 4 items (type=value_error.list.min_items; limit_value=4)
geometry -> coordinates -> 0 -> 3
  ensure this value has at least 4 items (type=value_error.list.min_items; limit_value=4)
geometry -> coordinates -> 0 -> 4
  ensure this value has at least 4 items (type=value_error.list.min_items; limit_value=4)
geometry -> type
  unexpected value; permitted: 'GeometryCollection' (type=value_error.const; given=Polygon; permitted=['GeometryCollection'])
geometry -> geometries
  field required (type=value_error.missing)

However this does not happen if Feature is omitted:

{
    "type": "Polygon",
    "coordinates": [
        [
            [-55.9947406591177, -9.26104045526505],
            [-55.9976752102375, -9.266589696568962],
            [-56.00200328975916, -9.264041751931352],
            [-55.99899921566248, -9.257935213034594],
            [-55.99477406591177, -9.26103945526505],
        ]
    ],
}

Result:

1 validation error for Polygon
coordinates
  All linear rings have the same start and end coordinates (type=value_error)

Can you look into that?
Thanks.

[vincentsarago]

@svaccari the first verbose error is because Pydantic will try to check all the geometry types instead of focusing on just the Polygon. Maybe there is something to explore there

edit:

I think we should use https://github.com/developmentseed/geojson-pydantic/blob/main/geojson_pydantic/geometries.py#L246 in https://github.com/developmentseed/geojson-pydantic/blob/main/geojson_pydantic/features.py#L29-L34

[eseglem]

Depends on #94 (types as Literals). But this is 90% solved by the following:

from typing_extensions import Annotated
...
Geometry = Annotated[
    Union[Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon],
    Field(discriminator="type"),
]

The error would then just be:

pydantic.error_wrappers.ValidationError: 3 validation errors for Feature
geometry -> Polygon -> coordinates
  All linear rings have the same start and end coordinates (type=value_error)
geometry -> type
  unexpected value; permitted: 'GeometryCollection' (type=value_error.const; given=Polygon; permitted=('GeometryCollection',))
geometry -> geometries
  field required (type=value_error.missing)

I haven't quite figured out getting rid of the GeometryCollection one yet. But at least its significantly improved.

[eseglem]

Took a bunch of iterations, but got it:

class Feature(GenericModel, Generic[Geom, Props]):
    ...
    geometry: Annotated[Union[Geom, None], Field(..., discriminator="type")]

And then you get

pydantic.error_wrappers.ValidationError: 1 validation error for Feature
geometry -> Union[Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon] -> Polygon -> coordinates
  All linear rings have the same start and end coordinates (type=value_error)

Edit: Updated to be required field.